M. Mihailescu, H. Endo, J. Allgaier, M. Monkenbusch, D. Richter

Using Neutron Spin Echo spectroscopy in combination with Dynamic Light Scattering we performed an extensive investigation of the bicontinuous (L3) phase in microemulsions. The dynamical behaviour of different surfactant systems (CloE4, CloE4 mixed with polymeric cosurfactant - PEP1O/PEO1o and AOT) was studied under comparable conditions, at different length scales. The analysis reveals stretched exponential relaxation with q**3 scaling ( q=momentum transfer) and an exponent of 0.75 in the asymptotic high q limit, and exponential relaxation with q**2 scaling at low q. On a local scale the relaxation rate increases almost linearly as function of the structure length -x. At intermediate length scales the relaxation rate in bulk contrast shows a minimum at q = qO ( the correlation peak position). Evidence for the modified elastic properties and additional interaction of the amphiphilic layers due to the polymer presence can only be found on a global scale.